V LTD sti type RA

I read that wrx type ra's rev limiter is 8250 and the sti type ra rev limits at 7500. my ver2 rev limiter is at 7750.

can some1 expalin this? do the ver 1-6 vary anyway? is there a common rule?

i workied out that it does 19mph in 5th gear taking it to 140mph so if some1 else has a deiiferent type RA and they do 500rpm more thats nearly 150mph.

thanks in advance